<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
</head>
<body>
    <script>
      debugger;
        var a = {n:1};
        console.log(a)
        var b = a;
        console.log(b)
        a.x = a = {n:2}
        console.log(a)
        console.log(b)
        
    </script>
</body>
</html>